The new energy concept of Gaznat's dispatching center and the Innovation Lab thereof.
GreenGas uses network convergence to optimize the site's renewable energy potential, decarbonize its industrial activities, and recover the captured CO2 in the form of by-products.
Innovation to support the energy transition!
The dispatching center, the nerve center for monitoring gas movements in western Switzerland's high-pressure transmission networks, has been the subject of a comprehensive review since 2018. As a safety measure due to the site's strategic function, and in order to implement its vision of CO2-neutral gas by 2050, Gaznat carried out a study to determine the site's energy needs and its potential in terms of renewable energies.
At the same time, Gaznat keeps on investing in research to sustainably decarbonize its activities through a competence center on the capture, storage and use of CO2 for the production of syngas, in partnership with the Ecole Polytechnique Fédérale de Lausanne (EPFL). This strategic cooperation with EPFL has resulted in two innovations ready for industrial testing: the methanation reactor and nanopore graphene membranes.
The integration of the R&D program into the reshaping of the dispatching center has given rise to the GreenGas project: a unique energy project in French-speaking Switzerland, featuring the largest industrial-scale laboratory in this area for the development of CO2-neutral renewable gases, the Innovation Lab, inaugurated on August 30, 2023.
Map of the dispatching center at Aigle - 2023In line with Gaznat's core business, the GreenGas value chain is based on the production of CO2-neutral syngas.
A major objective of this new energy concept is to maximize the use of local renewable energy potential, while guaranteeing the site's security of supply - a top priority.
At the same time, GreenGas relies on new technologies resulting from strategic cooperation with EPFL, namely the methanation reactor and carbon capture membranes implemented on site. Through its Innovation Lab, the project will also foster the development of other emerging energy-related technologies, and provide a scalable testing platform, available primarily to third parties such as Swiss research institutes and start-ups. The ultimate stage of these Gaznat-funded projects in an industrial environment will be to commercialize these technologies of the future.
The GreenGas concept and its Innovation Lab are taking shape around a set of interconnected modules and processes whose construction began in 2022 and will continue throughout 2023.
Schematic diagram of the GreenGas concept with its central Power-to-Gas plantTogether with the electrolyzer, the catalytic methanation reactor is the central component of the Power-to-Gas plant.
This technology breaks down into two stages: first, the electricity generated by the photovoltaic panels is converted into hydrogen by electrolysis; then this hydrogen, combined with a CO2 source, is injected into an innovative, high-efficiency methanation reactor to produce renewable non-fossil gas.
After a single pass through the reactor, the conversion rate of carbon dioxide and hydrogen injected into the reactor into syngas reaches an efficiency of over 99%, a feature that makes this methanation technology unique.
The syngas produced by the methanation reactor, with the same properties as natural gas and recognized as CO2-neutral, is injected directly into the low-pressure natural gas network for end-use by residential and industrial customers.
This methanation reactor is 225 times more powerful than the prototype from its original laboratory. Its thermal power is 225 KWth. The thermal energy dissipated by both the electrolyzer and the methanation reactor is recovered and injected into the heating microgrid to cover more than half the needs of the dispatching operation buildings.
Graphene membranes to capture CO2 from flue gases from the site's combined heat and power plants complete the Power-to-Gas installation at Aigle.
Graphene is an ultra-thin, flexible yet exceptionally strong material. It is totally impermeable to gases, making it a particularly interesting medium for their separation. Thanks to an oxidation technology that creates extremely small pores in graphene in a regulated manner, a selective flow is obtained that recovers carbon dioxide (CO2) and blocks nitrogen (N2).
This property is of interest for carbon capture in flue gases composed of a low percentage of carbon dioxide in nitrogen, which is the case for the cogeneration plant operating at Aigle, emitting a flue gas containing 11.8% CO2.
These membranes are able to capture 10 kg of CO2 per day, and eventually 45 kg per hour. This process will produce CO2 with a purity of 98%, which can then be stored in liquid form for subsequent injection into the methanation reactor to generate CO2-neutral syngas.
Graphene network separating carbon dioxide from nitrogenCapturing CO2 and using it as a raw material in the methanation reactor is a particularly promising way of decarbonizing the gas chain.
In 2015, Gaznat and EPFL created a chair to capture CO2 at its source and valorize it in the form of by-products. It was the team of Prof. Kumar Varoon Agrawal, Head of the Advanced Separation Laboratory (LAS), who brought the membrane innovation to maturity at EPFL Valais Wallis in Sion, within the Institute of Chemical Sciences and Engineering (ISIC), which focuses in particular on renewable energies, sustainable chemistry and materials for environmental protection. The nanopore membranes developed are patented by Gaznat.
The GreenGas energy concept was created with the help of some twenty partners, suppliers and service providers. Perfect coordination was required between the construction of the site shell and the installation of the various technological components, while maintaining absolute onsite security.
The final design and construction of the scaled-up methanation reactor at Aigle is the result of close collaboration between the Laboratory of Materials for Renewable Energies (LMER), headed by Prof. Andreas Züttel, and GRZ Technologies, a spin-off from EPFL Valais Wallis, which had already developed the pilot methanation reactor implemented at the measurement and regulating station in Sion.
The Innovation LabGRZ Technologies stands out for its expertise in the field of hydrogen, in particular its innovative storage in metal hydrides, another pioneering technology integrated into GreenGas.
The CEO and co-founder of GRZ Technologies, Noris Gallandat, PhD in mechanical engineering, affiliated to EPFL between 2016 and 2022, was a key interlocutor in this project. The long-standing partnership between Gaznat and the founding team of GRZ Technologies ensured an excellent understanding of the issues at stake in the GreenGas project and its success.
